1. Field of the Invention
The present invention relates a method and apparatus for discriminating a color format of a broadcasting signal, and particularly to such a method and apparatus, which permit a rapid discrimination of the color format.
2. Description of the Related Art
There have conventionally been known receiving apparatus such as a television receiver, which is compatible to a broadcasting signal in accordance with a plurality of color formats such as the NTSC format system and the PAL format system. In such a receiving apparatus, it is necessary to discriminate the color format of the broadcasting signal as received and execute the signal processing in accordance with the corresponding color format. In the conventional receiving apparatus, the predetermined color format, for example the NTSC format system has been set as the signal processing mode so that a receiving step is continued without converting the color format into the other format when the normal signal processing can be conducted. When the normal signal processing cannot be conducted, it is discriminated the type of color format with which the broadcasting signal as received has been processed, based on signals after demodulation in accordance with the NTSC format system. The color format of the broadcasting signal is discriminated and a switching operation of the receiving apparatus is carried out to execute the signal processing in accordance with the discrimination results, thus permitting to cope with the plurality of color formats.
In the conventional method, the color format of the broadcasting signal as being received is discriminated on the basis of resultant signals (i.e., color signals), which have been obtained after completion of separation of the luminance signal and the color signal from the broadcasting signal in accordance with the prescribed color format. As a result, much time is required to carry out the discrimination step of the color format, thus making it difficult to conduct a rapid stitching operation corresponding to the color format.